Can not use key 'o' to change cursor when visual mode blockwise via Ctrl-v

[WangRongda]

Is this a BUG REPORT or FEATURE REQUEST? (choose one):
A feature like native vim
What happened:
I press ctrl-v to select block text, then I press o but nothing happen
What did you expect to happen:
Change cursor to left side from right side or right side to left, so I can expand another side text selected.
I found multiple cursor is a alternative mothod in horizontal, but what about vertical expand.
How to reproduce it (as minimally and precisely as possible):

Environment:

• Extension (VsCodeVim) version:0.11.2
• VSCode version: 1.21.1
• OS version:4.15.9-1-ARCH